Liveable wage for software development?

I pitched the idea of having some T Shirts and other merchandise made in the FreeCAD forum, and it seemed like several people would be interested. Any thoughts on this design, especially the font? The image above is a quick-and-dirty sketch, I’d either find a better resolution logo image or redraw it if necessary, and fix the colours obviously.

While this project is ongoing, proceeds would go to me, but afterwards they would go to the project in general.